The present invention relates generally to photographic equipment and more particularly to a mechanism for enabling the parts of a photographic camera assembly to be rotated in order to change the image position within the camera.
In the photographic arts, situations arise where during the exposure of film, the camera may be rotated from a horizontal to a vertical position, or vice versa, during shooting of the same scene. With objective lenses which may be heavy or bulky, a tripod is used to support the camera by supporting the bulky or heavy lens barrel of the lens assembly and it is common practice in the prior art to revolve the camera body together with the lens barrel.
Management of an assembly of this type requires laborious manual manipulation, particularly when the angular position of the image format in the camera is to be changed rapidly. Furthermore, problems arise because of the weight of the lens assembly and it often occurs that the tripod is unintentionally displaced from its fixed position, thereby giving rise to deviation of the distance between the object and the film plane or image plane in the camera. Additionally, the framing point may be unintentionally altered and there thus necessarily occurs the requirement for readjusting focusing of the lens and for incurring the possibility of accidental shifting of the picture area.
In photographic devices involving interchangeable lens assemblies, there is provided a mechanism for revolving the image format on the camera through an angle of, for example, 90 degrees while maintaining the operative connection between the exposure control mechanism in the camera and the diaphragm device in the lens barrel. However, this mechanism tends to be large in size and weight and is relatively bulky to handle. Thus, in order to properly support the lens assembly on the tripod, the camera must be revolved along with the lens barrel relative to the stationary tripod about the optical axis of the lens assembly. As a result, the necessity arises for providing a bearing mechanism or gear device between the tripod and the lens barrel. This produces disadvantages in that a necessity arises for increasing the diameter of the lens barrel and for increasing the complexity of the mechanism.
In view of the foregoing, the present invention is directed toward providing a mechanism for enabling an image on a camera to be revolved whereby the camera body may be rotated through a desired angle, for example 90 degrees or 180 degrees, without causing a shift in the sharpness of the image plane or the picture area and which may operate effectively despite heavy weight of the lens barrel to enable a desired orientation of the angular position of the image frame by a quick and easy manipulation of the assembly.
A further aim of the invention is to provide a revolving mechanism which makes it possible to revolve the image frame while simultaneously maintaining operative connection between an exposure control mechanism in the camera body and the diaphragm device in the lens assembly.
Furthermore, the invention is directed toward providing a revolving mechanism capable, upon revolution of the image frame about the optical axis through a specified angle, of latching the camera body in a predetermined position relative to the lens assembly so that the camera may be held in that position.
An advantageous feature of the mechanism of the invention is that it enables the aforementioned operational features to be achieved with a lens assembly which may be designed similar to conventional structures, thereby avoiding the necessity for increase in the diameter of the lens barrel and in the complexity of the structure and of the weight thereof.